An automotive vehicle having an idle stop system has been proposed. The idle stop system is used as one of techniques to reduce a fuel consumption of an automotive vehicle, and stops an engine in the case of the engine idling at traffic lights so that the fuel consumption of the vehicle is reduced.
However, in this idle stop system, when an air-conditioner is required for operating, the idle stop system should not operate because the engine is required to drive an air-conditioner compressor. As a result, the idle stop system does not work effectively.
To solve the above problem, a hybrid compressor is proposed (JP-A-2000-229516). The hybrid compressor is a compressor integrated with a motor. When an engine is running, the engine drives the compressor. When the engine stops, a connection between the engine and the compressor is released so that the motor drives the compressor. However, the compressor in this prior art necessitates three rotary electric machines including an alternator. In some cases of this prior art, the compressor necessitates two inverters. Therefore, the construction of the hybrid compressor is much complex.
To solve this problem, another system is proposed in U.S. Pat. No. 5,896,750. In this system, a motor-generator and a compressor are connected to an engine by a belt through a one-way clutch.
However, this prior art has a problem that because the one-way clutch is mounted on a crankshaft pulley of the engine, the engine length becomes long. Accordingly, it is difficult to mount the engine in a front-engine/front-wheel-drive vehicle.
Considering these problems, the inventors have applied for patent (US 2002-0147531 A1). In this patent application, equipment includes a planetary gear system, which distributes a torque of a first shaft (i.e., a carrier) transmitted from an engine. The torque of the first shaft is distributed to a motor-generator connected to a second shaft (i.e., a ring gear) and a compressor connected to a third shaft (i.e., an sun gear). Further, the equipment includes a clutch disposed between the second shaft and the first shaft or between the second shaft and the third shaft, so that the third shaft can be locked by a lock system.
However, the accessory-driving equipment for an automotive vehicle with the planetary gear system has a difficulty that a reduction gear ratio of a motor-generator to the engine is limited to be small in the case of an engine starting. Therefore, it is difficult to start a large displacement engine by operating this accessory-driving equipment.